Relay actuated overhead door safety catch



Feb 11, 1969 H. M. M DANIEL ET 3,426,329

RELAY ACTUATED OVERHEAD DOOR SAFETY CATCH Filed Jan. 2. 1968 L .E mw m m 5 www N m m m T W m ME mm HE Y B United States Patent Office 3,426,829 Patented Feb. 11, 1969 3 Claims ABSTRACT OF THE DISCLOSURE A time-delay relay released safety catch is adapted to intercede across the travel path of overhead guide rollers and/or their support shafts, to prevent the fall of the door in the event of failure of the counterbalancing system.

Background of the invention This invention relates to an overhead door safety device to prevent accidental falling of overhead doors.

' Overhead doors of the type to which this invention is particularly directed, typically comprise a multiplicity of hinged horizontal panels having guide rollers which operate within a track permitting the door to be raised from a relatively lower closed vertical position to a relatively upper open horizontal position. In many instances, to facilitate the raising and lowering, a counterbalance means is provided to assist in raising the door and prevent the rapid acceleration of the door as it is being closed. In many instances manufacturers use heavy duty coil type springs which uncoil during the raising operation and hence assist the operator and, conversely, wind up during the lowering operation and hence prevent the rapid acceleration of the door to the vertical closing position. In many instances these doors weigh as much as three hundred pounds or more and if the spring or counterbalance means breaks during the raising operation the operator must then support the full weight of the door which in many instances becomes impossible to do causing injury and damage to persons and property. Many overhead doors include glass paneling which shatters and breaks causing additional inury.

Mechanically actuated safety catches have been heretofore taught as in US. Patents 3,258,062; 1,875,599; and 2,068,543. Patents in the elevator arts include safety catches which largely become operable upon breakage of a supporting cable and/or the inertia of the falling door or elevator car. Electrical relays have been used in conjunction with vertically sliding doors such as in 2,513,152 and in 3,258,062. Such devices however have not provided an electrically actuated time-delay released safety catch which is incorporated into the path of the overhead door guide rollers and/ or support shafts when the door is in a raised position.

Accordingly it is an object of this invention to overcome the problems associated with many overhead doors and provide a safety catch which prevents the falling of the door in the event of failure of the counterbalancing means.

Another object of this invention is to provide a relay actuated safety catch which permits movement of the overhead door rollers in one direction but prevents movement in the other direction until time-delay released by the operator.

Summary A relay actuated safety catch is adaptable to be attached, preferably to an overhead door guide rail system wherein the safety catch mechanism is adept to intercede across the path of either the overhead door rollers and/or its connected shaft in order to prevent the downward movement of the door in the event of failure of the counterbalancing and/or lifting mechanism. A time delay switch is incorporated with the relay to maintain the safety catch out of the path of the roller when it is desired to lower the door then automatically intercede into the path again after a predetermined time ready for use upon the next raising of the overhead door.

Brief description of the drawings FIGURE 1 is a partial elevational view depicting a typical overhead door and a relay actuated catch of this invention.

FIGURE 2 is a side partial sectional view of the relay actuated mechanism of this invention.

Description of the preferred embodiment Referring now to FIGURE 1 the safety catch of this invention is adapted to be used in conjunction with a typical garage or enclosure 10 having an overhead door 11 which includes a multiplicity of panels 12 connected by hinges 14 which permits pivotal movement between the sections. In many instances each hinge includes a bracket 16 to which is attached a guide rollers 18 which extends from a shaft 20 into a guide railing or track 22. Usually, this railing extends on each side of the overhead door and includes a vertical portion 22 extending upwardly to a substantially horizontal portion 24 interconnected by graduated curved portion. A cable 26 extends vertically to a drum 28 which permits winding of the cable as the door is raised. The drum 28 is typically attached to a horizontal shaft which extends to the other side of the door where a similar cable drum is attached, and not shown in these views. A typical counterbalancing system for overhead doors is shown in Patent No. 3,258,062 includes a coil spring one end of which is attached either to the shaft or the cable drum and the other end of which is fixed with respect to the drum or shaft such that in operation the spring will be wound and unwound to provide a counterbalancing force. It is to be understood however that other well known types of counterbalancing means may be utilized in lieu of that heretofore described and shown in the aforesaid Patent No. 3,258.062.

The safety catch of this invention is generally indicated by the numeral 30, which is attached to the rail 22 by a plurality of fasteners 32. The safety catch generally includes a catch arm 34, a relay 36 and a switch 38. The arm 34 is adapted to rotate about shaft 40 and is interconnected to the relay arm 42 by a linkage 44 a coil spring 46 tends to normally bias the catch into the safety position as shown by the solid lines in FIGURE 2 so as to be within the path of either the guide rollers 18 or appended shaft 20. An electrical supply system 48 is adapted to supply power through switch 38 to the relay 36.

In operation, assuming the door is in the lower closed position the relay 36 is inactive but the catch 34 by reason of the bias from spring 46 positions the safety catch as shown in solid lines of FIGURE 2. That is, it is across the travel path of either the guide roller 18 or its appended shaft 20. During the upward movement of the door as each shaft 20 strikes the catch 34 it will be caused to pivot against the bias of spring 46 until the desired position of the door is reached. As such any downward movement of the rollers and/or shafts 20 will strike surface 50 of the catch and be retained as the catch abuts the edge 52 of the guide rail or housing 54 of the relay assembly. In this position any breakage of the cable 26 or the counterbalancing mechanism will prevent the vertical drop of the door 11. However, when it is desired to lower the door, switch 38 is actuated by knob 39 which electrically actuates relay 36 drawing arm 42 downward, and its associated linkage 44, pulling safety-catch 34 to the position shown by the dotted line allowing door 11 to be lowered to the position as shown in FIGURE 1.

By a suitable time delay mechanism, for example one minute, incorporated in switch 38 causes the relay to remain actuated and in the fixed position described. Upon release of the time delay mechanism the electrical current is deactivated allowing the relay to release its arm 42 returning the safety catch to its position shown in solid lines of FIGURE 2.

Although this invention has been described with a certain degree of particularity, it is manifest that many changes may be made in the details of construction and configuration of the components without departing from the spirit and scope of this disclosure. Accordingly the detailed description is made by way of example only and not intended to constitute a limitation of the invention which is delineated in the appended claims.

What is claimed is:

1. A door construction comprising the combination of,

a plurality of panels hingeably pivoted to each other along horizontal axes,

a plurality of guide rollers suspended on shafts attached to the vertical edge of said panels,

a guide rail adjacent each of said vertical edges and contiguous to said rollers, said rail including a substantially overhead horizontal portion and an interconnected vertical portion, and a safety catch comprising,

a plate or housing attached to said rail,

a catch member pivotally connected to said plate for movement from a first position wherein a stop portion extends across the travel path of said rollers or said shafts to a second position out of said path, means to bias said catch member to said first position, an electrical relay core attached to said catch member to pivot same, upon actuation, to said second position, and

a switch electrically connected to said relay to actuate said relay.

2. The combination of claim 1 wherein said catch member is attached to vertical portion of said guide rail.

3. The combination of claim 1 wherein said switch is a time delay switch to actuate said relay for a given period of time.

References Cited UNITED STATES PATENTS 1,994,142 3/1935 Madsen 160-201 X 2,703,247 3/1955 Wolf ct al l-201 X FOREIGN PATENTS 540,320 5/1953 Canada.

PETER M. CAUN, Primary Examiner.

U5. (:1. X.R. 

